GPIO Configuration

1. Under the root directory of freelight-u-sdk, run the following command to enter the kernel menu configuration GUI.

   make linux-menuconfig

2. Enter the Device Drivers menu.

3. Enter the Pin controllers menu.

   

4. To enable the pinctrl driver, select the Pinctrl driver for StarFive SoC option. To enable the GPIO driver, select the Pinctrl and GPIO driver for StarFive JH7110 SoC option.

   

5. Save your change and exit the kernel configuration dialog.

After system boot-up, you can run the following commands to verify if the GPIO driver is working properly.

# cd /sys/class/gpio/ 
# ls
export	gpiochipO	gpiochip64	unexport
# echo 44 > export		
# ls			
export	gpio44	gpiochipO	gpiochip64	unexport
# cd gpio44/		
# ls			
active_low	direction	subsystem	value
device	edge	uevent	
# cat direction 
in
# cat value
1

The following code example configures two SoC pins (GPIO5 and GPIO6) to act as the UART0 serial port (TX/RX) with correct pin functions, direction, bias, and electrical settings. It is a child of the board’s top-level &gpio pin controller.

&gpio {
        uart0_pins: uart0-pins {
                uart0-pins-tx {
                        sf,pins = <PAD_GPIO5>;
                        sf,pin-ioconfig = <IO(GPIO_IE(1) | GPIO_DS(3))>;
                        sf,pin-gpio-dout = <GPO_UART0_SOUT>;
                        sf,pin-gpio-doen = <OEN_LOW>;
                };

                uart0-pins-rx {
                        sf,pins = <PAD_GPIO6>;
                        sf,pinmux = <PAD_GPIO6_FUNC_SEL 0>;
                        sf,pin-ioconfig = <IO(GPIO_IE(1) | GPIO_PU(1))>;
                        sf,pin-gpio-doen = <OEN_HIGH>;
                        sf,pin-gpio-din =  <GPI_UART0_SIN>;
                };
        };
};

Parameters:

• pins: Which physical pin is used for UART0 TX
• pinmux: Pin mux function select
• pin-ioconfig: Input enable and drive strength setting
• pin-gpio-dout: Output connection
• pin-gpio-doen: output enable